[GPI]

Leatherjackets (lawn pest) - Tipula paludosa and Nephrotoma
by GPI

Plants affected
Lawn grass, seedlings of vegetables and small plants in open soil and pots outdoors.

Season(s) present.
Summer mostly, but attacks can occour year round especially after a wet winter.

Leatherjacket, photo / picture / image.

Appearance of damage.
Yellow/brown dead patches on grass, and overall it may be slow growing. Gently tugging at the grass may result in it being pulled up, with little or no root growth.
Cuts and marks in the lawn from leatherjacket hunting birds.
New vegetable and other seedlings not developing due to severed roots.
Plants in pots never developing and lacking vigour
Bulbs failing to appear above ground.
Strawberries weakened and failing to produce fruit.

Cause
The larvae of the cranefly or daddy-long-legs known as the leatherjacket.
Each female cranefly place about 300 eggs into soil in late summer, the larvae then hatch in the autumn to begin feeding on roots.
The headless and legless tube-like larvae are grey/brown and up to two inches long (45mm). Their leathery outer skin is where the get their name.

Trouble?
Yes, leatherjackets are one of the worst pest of the lawn, especially one with poor drainage. They are also very damaging in a vegetable garden which has been recently converted from grass.

Organic or cultural control.
Ensure you have adequate drainage in your lawn, as eggs and young larvae thrive in damp conditions. Sandy soil will also show less occurrence of leatherjacket attack.
Encourage the bird population in your garden by providing trees and shrubs as shelter and feeding them occasionnaly. Your birds will keep the population of craneflys lowered resulting in less leatherjackets. Unfortunately there is a downside to the birds especially the ground feeders such as the blackbird, as they cut up the lawn in their search for leatherjacket grubs.
In the evening, water an area of soil/lawn and cover it with a sheet of black plastic, then in the early morning remove the cover to expose any leatherjackets which have come to the surface. Sweep them up and dispose or else vacate the area quickly and let the Starlings, blackbirds and robins pick them off.
For leatherjacket control you can, if the pots are manageable, pop the rootball out of the pot and pick off any visable grubs.
Digging over an area of leatherjacket infested soil with a fork will also bring the grubs to the surface to be eaten by birds that flock to any piece of freshly turned sod.
You can water on a a biological control from late August to October, a parasitic nematode called Steinernema feltiae. These nematodes attack the leatherjackets causing them to die out. Steinernema feltiae can be ordered through garden centres or online.

Other Control.
Applying slug pellets which contain Methiocarb will also reduce the leatherjacket population. Sprinkle them over the ground and lightly rake in.

Note: The use of slug pellets may result in a reduction in your gardens bird population.

Nature notes.
Please note that Irishgardeners.com does not advocate the removal of insect life, instead, this forum encourages wildlife preservation. However, there are occasions where a wildlife becomes a problem within the garden for certain people. Be aware that wildlife is a link in the chain of life, benefiting something or someone down the chain. Please at least think about this before you remove wildlife from your site.

DISCLAIMER: The control methods are suggested here as a matter of general information. Under Irish and EU law it is illegal to use any preparation as a pesticide/fugicide/herbicide that is not approved for such use. The author and the website accepts no responsibility for how a user may mix, use, store, or any effects the mixture or its elements may have on people, plants or the environment. The information here is for reference only and does not imply a recommendation for use. If you disregard this warning and make any of the preparations, you do so entirely at your own risk.

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